CHICAGO — The woman whose arguments led Massachusetts to become the first state to legalize marriages for same-sex couples is joining the legal team fighting Utah's ban on same-sex couples' marriages.

Gay & Lesbian Advocates & Defenders' Mary Bonauto has joined a growing team of lawyers defending two same-sex couples seeking to marry in Utah and one same-sex couple seeking to have their Iowa marriage recognized by the state. Bonauto will be joined by GLAD's legal director, Gary Buseck, and others at the organization.

The ban in Utah was one of 11 on the ballot in November 2004 — a wave of amendments that all passed and that many argued were a backlash to the Massachusetts decision won by Bonauto.

A decade later, she's now on the team that will soon be asking the Supreme Court to hear a case ending Utah's ban — a case that could end all such bans across the nation.

GLAD is joining Peggy Tomsic, whose firm, Magleby & Greenwod, defended the Utah same-sex couples from the start of the lawsuit and who successfully argued the case before the 10th Circuit Court of Appeals. GLAD is not the first to join Tomsic. After the couples' trial court win in December 2013, lawyers at the National Center for Lesbian Rights, including Kate Kendell and Shannon Minter, joined the team for the appeal to the 10th Circuit. In the past month, as the attention turns to the Supreme Court, former Acting Solicitor General Neal Katyal, now at Hogan Lovells, joined the team.

"We are thrilled to be adding Mary Bonauto, Gary Buseck and GLAD to the Utah legal team," Minter told BuzzFeed on Monday evening. "Mary and Gary bring an unparalleled depth of experience and expertise litigating the constitutional issues raised by these historic cases. NCLR and GLAD have a long history of working together, and we are honored to be partnering on such an important case at such a critical time in the movement for marriage equality."

Things are already heating up at the Supreme Court, as Utah officials earlier this month asked the justices to hear their appeal of the 10th Circuit ruling that the ban is unconstitutional, a filing called a certiorari petition. In an unusual move, the plaintiffs in the case — despite having won at the 10th Circuit — are expected to file a response supporting the state's request that the Supreme Court take up the appeal.

Bonauto told BuzzFeed tonight that she and her GLAD colleagues are "very excited" to be join what she called "such a strong team."

Of what they bring to the team, she pointed to GLAD's experience with legal fights for same-sex couples' relationship recognition from before the 2003 Massachusetts ruling through to her work filing the first litigation successfully challenging the Defense of Marriage Act and then supporting Edie Windsor's challenge to the law that eventually was heard by the Supreme Court.

"GLAD brings the perspective, insights, and distillation that come from long experience on marriage and the related issues, and the good sense to take nothing for granted," Bonauto said. "We've also won this issue in courts, and worked with others to win in state legislatures and at the ballot box. That has given us a deep feel for the concerns and hesitations out there and insights about how to make our case and find shared values that move us forward."

Specifically as to the DOMA litigation, she added, "We hope that the strategic thinking on DOMA — about how to get to a win on DOMA that would also position us to keep moving forward to marriage — will be useful here as well."

Mary Bonauto speaks to reporters after the 1st Circuit Court of Appeals heard arguments over the constitutionality of the Defense of Marriage Act in 2012.

Now, Bonauto and the GLAD lawyers — who coordinated the friend-of-the-court, or amicus, briefing for the Utah and Oklahoma cases at the 10th Circuit — will be working for the Utah plaintiffs themselves.

Evan Wolfson, the founder and president of Freedom to Marry, praised GLAD's addition to the team, saying that "the already stellar" legal team "is going all-star" by adding Bonauto and Buseck to the team.

"Not only did GLAD lead in teeing up the litigation strategy that brought down DOMA, but Mary was the unsung engine of the friend-of-the-court presentations made to the Supreme Court in both marriage cases last year," Wolfson said.

He said it is "urgent" that the Supreme Court act on the issue, adding, "The Utah freedom to marry case is super-clear and clean, and whichever case or cases the Court elects to hear, the collective presentation lawyers like this will make will be strong, compelling, and thorough."

In addition to the Utah case, certiorari petitions have already been filed with the court for cases out of Oklahoma and Virginia.

Other petitions could be coming in short order, as appellate arguments in cases from nine other states will have been heard before the justices return from their summer recess. Appellate arguments were heard earlier this month in cases out of Kentucky, Michigan, Ohio, and Tennessee by the 6th Circuit Court of Appeals. The 7th Circuit Court of Appeals is hearing arguments in challenges to Indiana and Wisconsin's bans on Tuesday, and the 9th Circuit Court of Appeals is hearing cases out of Idaho and Nevada, as well as Hawaii, in September.